By a vote of 17-9, the committee passed a bill crafted by its chairman, Sen. Carl Levin, D-Mich., designed to increase pressure on senior commanders to prosecute sexual assault cases by requiring a top-level review if they fail to do so. Levin’s proposal also makes it a crime to retaliate against victims who report a sexual assault and also calls on the Pentagon to relieve commanders who fail to create a climate receptive for victims.

The committee rebuffed a proposal in a bill by Sen. Kirsten Gillibrand, D-N.Y., to remove commanders from the process of deciding whether serious crimes, including sexual misconduct cases, go to trial. That judgment would have rested instead with seasoned trial lawyers who have prosecutorial experience and hold the rank of colonel or above. The committee also rejected a provision of Gillibrand’s bill that would have taken away a commander’s authority to convene a court-martial by giving that responsibility to new and separate offices outside a victim’s chain of command.

Echoing concerns voiced by the Joint Chiefs of Staff over Gillibrand’s bill, members who backed Levin said they feared taking commanders out of the legal process would create more problems than it would solve by undercutting the ability of officers to maintain good order and discipline in their units.

“I do not support removing the authority of commanders to prosecute sexual assault cases and putting that decision in the hands of military lawyers outside the chain of command,” said Levin, who acknowledged the military has a serious problem with sexual assaults in the ranks.

Levin’s proposals to prevent sexual assaults will be included in a sweeping 2014 defense policy bill. His legislation also includes a provision that would largely strip commanders of the power to overturn convictions in rape and assault cases. The change was initially recommended in April by Defense Secretary Chuck Hagel and is backed by the Joint Chiefs and many members of the House and Senate, including Gillibrand.

Under Levin’s legislation, the civilian secretaries of the military services would be required to conduct a review if a commander ignores the recommendation of a military lawyer to prosecute a sexual assault case.

Commanders actually are more likely to prosecute sexual assault cases than are military lawyers, Levin argued. He cited recent congressional testimony from commanders who said they have prosecuted sexual assault cases against the advice of military lawyers “because of the importance of the message that such prosecution sends to the troops.”

But Gillibrand, her voice rising, called Levin’s plan insufficient. While she agreed with parts of his plan, such as making retaliation a crime, she said it fails to force the changes needed to transform military culture in ways that would ensure victims that if they report a crime their allegations won’t be discounted and their careers won’t be jeopardized.

Gillibrand said the problem is not that commanders are dismissing the advice of the lawyers on their staffs. Sexual assault victims fear reporting the crimes within their chain of command, she said, and Levin’s bill does not change that. Her bill would, she said.

“If you look at the victims descriptions of what happens to them, their assailant is someone usually senior to them, someone up the chain, more decorated, a Purple Heart recipient, someone who has done great acts of bravery, and they see that the chain of command will not be objective,” Gillibrand said.

Only one Republican on the committee supported Gillibrand’s legislation: Sen. Ted Cruz of Texas, who said he was swayed by Gillibrand’s plea that victims have an impartial process for reporting crimes.

In a statement after the committee’s vote, Gillibrand said she planned to offer the provisions rejected by the committee as amendment to the defense policy bill when it is taken up by the full Senate. Her legislation has so far garnered 28 co-sponsors, including Sens. Patrick Leahy, D-Vt., chairman of the Senate Judiciary Committee, Chuck Grassley of Iowa, the Judiciary Committee’s top Republican, Barbara Mikulski, D-Md., chairwoman of the Senate Appropriations Committee, Dianne Feinstein, chairwoman of the Senate Intelligence Committee, and Thomas Carper, D-Del., chairman of the Homeland Security and Governmental Affairs Committee.

The Pentagon estimated in a recent report that as many as 26,000 military members may have been sexually assaulted last year, up from an estimated 19,000 assaults in 2011, based on an anonymous survey of military personnel. While the number of sexual assaults that members of the military actually reported rose 6 percent to 3,374 in 2012, thousands of victims were still unwilling to come forward despite new oversight and assistance programs aimed at curbing the crimes, the report said.

By week’s end, the House is scheduled to vote on its version of a defense policy bill that includes a number of sexual assault prevention provisions.

The House bill currently requires that anyone found guilty of rape, sexual assault, forcible sodomy or an attempt to commit any of those offenses receive a punishment that includes dismissal from military service or a dishonorable discharge.

Rep. Michael Turner, R-Ohio, plans to offer an amendment to the House bill that would make two years of confinement and a dishonorable discharge the mandatory minimum sentence for any service member convicted of rape or sexual assault. Imposing a tough, minimum sentence will serve as a deterrent to help prevent sexual assaults, according to Turner.

The House legislation eliminates the five-year statute of limitations on trial by court-martial for sexual assault and sexual assault of a child. It also establishes the authority for military legal counsel to provide legal assistance to victims of sex-related offenses and requires enhanced training for all military and civilian attorneys involved in sex-related cases.